Update commands and versions up until 'Starting your virtual machine'

Thanks again for writing this. Your tutorial has helped me and others quite a bit. This is me bringing some of the versions and commands up to date. Let me know if you have better direction for this as I'm new to Chef, Berkshelf, and Vagrant. I ran through your tutorial while figuring out what real commands or syntax were needed. Now I'm having at it to put the most recent versions into your guide.

It would be nice to have a new base image with a more recent version of chef. I ended up using a more recent CentOS 6.4 box.